Fawn mortality examined

The success of any population of animals is tied directly to its youngest generation and deer are no exception.

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By MARK SPENCLEYmark@cheboygantribune.com

Cheboygan Daily Tribune - Cheboygan, MI

By MARK SPENCLEYmark@cheboygantribune.com

Posted Feb. 27, 2013 at 8:20 PM

By MARK SPENCLEYmark@cheboygantribune.com

Posted Feb. 27, 2013 at 8:20 PM

The success of any population of animals is tied directly to its youngest generation and deer are no exception.

Whitetail fawns face a gauntlet of challenges before they reach adulthood. Cold winters difficult both before birth, when the mother is stressed by the elements, and after birth, when fawns face their first winter. Predation is another significant factor is fawn mortality, on that has received plenty of attention for biologists in recent years.

For the last several winters, Department of Natural Resources biologist Dean Beyer has been conducting a study on fawn mortality in the central Upper Peninsula. In an area where wolves are vilified as the deer herd’s biggest challenger, another K9 has proved more lethal.

“As far as predation, coyotes have killed more fawns than any other predator in our study,” he said.

In the first three years of this study, 142 fawns were radio collared, 53 of which were killed by predators. Coyotes accounted for nearly half, or 26 of those kills. Bobcats, wolves, bears, and bald eagles combined for 22 kills, wolves only killing five fawns.

Radio collars are used to track both deer and predators, tracking movement and ultimately mortality.

While predators play a significant role in fawn survival, there are other factors. In fact, other factors, mainly weather, could increase the rate at which fawns fall victim to predators.

“This is preliminary data and there is a lot of important interaction in all of the factors that affect fawn mortality,” Beyer noted. “We’re still working to see how all of these interact.”

Weather looks to be one factor that has a measurable impact on fawn mortality. In 2009, a year with a particularly harsh winter, the fawn survival rate was 37 percent. During the following year, 2010, a mild winter yielded a 61 percent survival rate. Though a tie between weather and predation looks to exist, biologists are still looking into it.

“If animals are weakened they are more vulnerable,” said Beyer. “That could play into predation.”